[PATCH 2/3] slub: record page flag overlays explicitly

From: Andy Whitcroft
Date: Thu May 15 2008 - 13:20:35 EST



SLUB reuses two page bits for internal purposes, it overlays PG_active
and PG_error. This is hidden away in slub.c. Document these overlays
explicitly in the main page-flags enum along with all the others.

Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxx>
---
include/linux/page-flags.h | 4 ++++
mm/slub.c | 4 ++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 2cc1fb1..2e88df6 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -103,6 +103,10 @@ enum pageflags {

/* XEN */
PG_pinned = PG_owner_priv_1,
+
+ /* SLUB */
+ PG_slub_frozen = PG_active,
+ PG_slub_debug = PG_error,
};

#ifndef __GENERATING_BOUNDS_H
diff --git a/mm/slub.c b/mm/slub.c
index a505a82..fd7c61a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -102,10 +102,10 @@
* the fast path and disables lockless freelists.
*/

-#define FROZEN (1 << PG_active)
+#define FROZEN (1 << PG_slub_frozen)

#ifdef CONFIG_SLUB_DEBUG
-#define SLABDEBUG (1 << PG_error)
+#define SLABDEBUG (1 << PG_slub_debug)
#else
#define SLABDEBUG 0
#endif
--
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